Sessions
Use the 'Save session...' entry in the File menu to save a session. Session means that all open tabs will be saved. When loading a session all tabs of the session will be restored (i.e. all the log files will be opened).
A session file is a small XML file which contains references to the persistence files of the log files. When saving a session, persistence file saving is forced even if persistence saving is disabled in the settings.
To load a session use the 'Load session...' menu entry. You can also drag'n'drop a session file onto LogExpert or use a session file as command line argument.